Discord bot logs are full of messages about connection attempts to closed rooms

[brianpeiris]

In order to continue debugging issues with the discord bot, we should resolve this issue that floods the bot's logs with errors about closed rooms.

The errors look like:

Phoenix: channel dropping outdated message {                            
  topic: 'hub:******',                                                 
  event: 'phx_reply',                                                   
  payload: {                                                            
    response: { message: 'Hub no longer accessible', reason: 'closed' },
    status: 'error'                                                     
  },                                                                    
  joinRef: '******'                                                    
}                                                                       

[brianpeiris]

Fixed in #117